Although William Playfair is often credited with having created the first bar graph around 1780, Nicole Oresme used a graph-like planar illustration in a 14th-century work to demonstrate the acceleration of an object over time. Because of similarities in Oresme's illustration to modern bar charts, his usage can be considered a forerunner of the current method of using visual elements to display numerical information. Joseph Priestly, another early proponent of using visual images to convey numerical concepts, published a timeline type of graph in 1765 that incorporated bars of varying lengths.
The graph used by Playfair about 20 years after Priestly was the first to divide numerical data into discrete groupings. This particular feature of Playfair's work is what has earned him the greater amount of recognition for his visual depiction of data. Playfair was likely inspired by his review of Priestly's earlier document. More than 100 publications are attributed to Playfair, but he ran afoul of the law in some of his enterprises and died in poverty. His chart and graph styles have, however, remained in use.